 /*
  * Copyright (C) 2009 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 package com.xiaoma.myaudience.util;
 
 /**
  * Container to ease passing around a tuple of two objects. This object provides a sensible
  * implementation of equals(), returning true if equals() is true on each of the contained
  * objects.
  */
 public class Pair<F, S> {
     public final F first;
     public final S second;
 
     /**
      * Constructor for a Pair. If either are null then equals() and hashCode() will throw
      * a NullPointerException.
      * @param first the first object in the Pair
      * @param second the second object in the pair
      */
     public Pair(F first, S second) {
         this.first = first;
         this.second = second;
     }
 
     /**
      * Checks the two objects for equality by delegating to their respective equals() methods.
      * @param o the Pair to which this one is to be checked for equality
      * @return true if the underlying objects of the Pair are both considered equals()
      */
     public boolean equals(Object o) {
         if (o == this) return true;
         if (!(o instanceof Pair)) return false;
         final Pair<F, S> other;
         try {
             other = (Pair<F, S>) o;
         } catch (ClassCastException e) {
             return false;
         }
         return first.equals(other.first) && second.equals(other.second);
     }
 
     /**
      * Compute a hash code using the hash codes of the underlying objects
      * @return a hashcode of the Pair
      */
     public int hashCode() {
         int result = 17;
         result = 31 * result + first.hashCode();
         result = 31 * result + second.hashCode();
         return result;
     }
 
     /**
      * Convenience method for creating an appropriately typed pair.
      * @param a the first object in the Pair
      * @param b the second object in the pair
      * @return a Pair that is templatized with the types of a and b
      */
     public static <A, B> Pair <A, B> create(A a, B b) {
         return new Pair<A, B>(a, b);
     }
 }
